The primary objective of this research is to provide data that can be used to evaluate the safety of present and future ultrasound ophthalmic systems employed in diagnosis. Toward this goal, determinations will be made of ultrasonic exposure levels needed to produce damage to ocular and orbital tissues of insonified rabbits. The safety of these exposures will be evaluated on the basis of comprehensive program of tissue analysis. Accurate determination of the applied radiation levels will be accomplished by experimental and analytic techniques and determinations of the acoustic properties of ocular and orbital tissues. Damage mechanisms will be studied so that this data base can be extrapolated to humans. The knowledge gained from this research will provide a foundation for the formulation of ultrasonic safety standards applicable to the design of ultrasonic equipment and the planning of clinical procedures. BIBLIOGRAPHIC REFERENCES: Lizzi, F.L., Katz, L., St. Louis, L. and Coleman, D.J., "Applications of Spectral Analysis in Medical Ultrasonography," Ultrasonics, 14: 7-80, 1976. Lizzi, F.L., Packer, A.J. and Coleman D.J., "Animal Studies of Cataracts Produced by High Intensity Ultrasonic Energy," Ultrasound In Medicine, Vol. II, edited by D. White and R. Barnes, New York, Plenum Press, 1976, pp 525-526.